Ten endangered pygmy elephants have been found dead in suspicious circumstances in Malaysia, according to reports.

Sen Nathan, head veterinarian at the Gunung Rara Forest Reserve in Sabah state on the island of Borneo, said officials "highly suspect" the animals were poisoned, but tests are still to be carried out to determine whether they were deliberately harmed, BBC News reported.

"It was actually a very sad sight to see all those dead elephants, especially one of the dead females who had a very young calf of about three months old. The calf was trying to wake the dead mother up," he said, according to the BBC.

Nathan added the elephants, aged between four and 20, were believed to be from the same family group.

Malaysia’s The Star newspaper said the first elephant died on Dec. 29 and the last was found on Jan. 24.

The paper reported that the dead animals were found in an area that it described as an “industrial tree plantation.”

The Star said it was not known how the elephants had died, and noted it was possible they had eaten poisonous plants or pesticides.

The BBC cited Masidi Manjun, environmental minister for the Sabah area, as saying it was “a sad day for conservation and Sabah.”

Sabah Wildlife Department via Reuters

Malaysia's wildlife officials inspect a dead pygmy elephant.

Conservation charity WWF runs an “adopt a pygmy elephant” campaign.

According to its website, the animals are found “only on the northeast tip of the island of Borneo, and inhabit forests near water sources and grasslands. “